Memory sub-system data retention via refresh

ABSTRACT

A method includes providing, when delivery of power to a memory sub-system comprising a plurality of non-volatile memory components from a main power supply is interrupted, power from an auxiliary power supply to a portion of a controller interfacing with the non-volatile memory components. The portion of the controller may utilize the power from the auxiliary power to supply to: responsive to a prediction, generated when the delivery of the power from the main power supply to the memory sub-system is interrupted, that a particular portion of the plurality of non-volatile memory components will experience an impending data loss event, perform a targeted refresh operation of data stored in the particular portion.

TECHNICAL FIELD

Embodiments of the disclosure relate generally to memory sub-systems, and more specifically, relate to memory sub-system data retention via refresh.

BACKGROUND

A memory sub-system can include one or more memory devices that store data. The memory devices can be, for example, non-volatile memory devices and volatile memory devices. In general, a host system can utilize a memory sub-system to store data at the memory devices and to retrieve data from the memory devices.

BRIEF DESCRIPTION OF THE DRAWINGS

The present disclosure will be understood more fully from the detailed description given below and from the accompanying drawings of various embodiments of the disclosure.

FIG. 1 illustrates an example computing system that includes a memory sub-system in accordance with some embodiments of the present disclosure.

FIG. 2 illustrates an example computing system that includes a memory sub-system in accordance with some embodiments of the present disclosure.

FIG. 3 is a flow diagram corresponding to memory sub-system data retention via refresh in accordance with some embodiments of the present disclosure.

FIG. 4 is a block diagram of an example computer system in which embodiments of the preset disclosure may operate.

DETAILED DESCRIPTION

Aspects of the present disclosure are directed to memory sub-system data retention via refresh, in particular to memory sub-systems that include a data retention component. A memory sub-system can be a storage system, storage device, a memory module, or a combination of such. An example of a memory sub-system is a storage system such as a solid-state drive (SSD). Examples of storage devices and memory modules are described below in conjunction with FIG. 1 , et alibi. In general, a host system can utilize a memory sub-system that includes one or more components, such as memory devices that store data. The host system can provide data to be stored at the memory sub-system and can request data to be retrieved from the memory subsystem.

Data may be stored at the memory sub-system utilizing an electrical charge. For example, data values may be stored as an electrical charge stored at the memory sub-system. The electrical charge may be subject to modification and/or degradation. For example, over time (in the absence of a power supply, the electrical charge may leak or. In addition, exposure to various conditions, such as elevated temperatures, may contribute to and/or accelerate such modifications and/or degradations.

For example, a memory sub-system can experience fluctuations of characteristics of the memory sub-system. For example, a memory sub-system can experience fluctuations in thermal characteristics, such as operating temperature. For example, because electrical current is utilized to provide power to the memory sub-system, the memory sub-system can exhibit temperature fluctuations during operation. Further, a memory sub-system can experience temperature fluctuations based on the environment in which the memory sub-system is deployed. As such, exposure to temperature fluctuations can occur regardless of whether the memory sub-system is operational and even when the memory sub-system is not operational and/or in the absence of power from a main power supply.

Although some amount of temperature fluctuation is tolerable within a memory subsystem, the memory sub-system can be adversely affected if such temperature fluctuations meet certain criteria (e.g., exceed thresholds). For example, ambient temperatures above 35° C. can shorten the life of a memory-subsystem and/or its data. Memory sub-system reliability and data fidelity may be significantly compromised above 55° C. For example, if a memory sub-system is exposed to temperatures that are greater than a threshold safe temperature range, the memory subsystem can experience degraded performance and, in some instances, can fail. For example, in some embodiments, if the temperature of the memory sub-system (or of components of the memory sub-system) reach or exceed a threshold temperature for a threshold amount of time while a main power supply is removed from a memory sub-system a data loss event may occur to the data stored in the memory sub-system.

A data loss event may include the degradation and/or loss of data stored in the memory devices of the memory sub-system such that the stored data is no longer present and/or no longer accurately represents its original values. In some examples, a data loss event may be marked by an error rate of the data stored in the memory sub-system exceeding the error correction capability of an error correction component of the memory sub-system.

In order to avoid data loss events during operation of a memory sub-system, active mitigation measures may be utilized to control the fluctuations of the characteristics of the memory sub-system. For example, an active cooling component such as a fan may be utilized in order to cool the memory sub-system during operation. The active mitigation measures rely on and/or utilize power supplied by a main power supply provided to the memory sub-system during operation. For example, a device including the main power supply may be physical attached (e.g., via a power cord, backplane, power bus, etc.) to a main power source such as an outlet connected to an electrical power transmission grid. The main power supply may be utilized to run the active cooling component in addition to operating other components of the device while the device is powered on and receiving its full allocation of a power supply.

As mentioned above, a memory sub-system can experience temperature fluctuations based on the environment in which the memory sub-system is deployed. Such environmental influences may persist regardless of the power state (e.g., powered on, powered off, sleeping, disconnected from the main power supply, etc.) of the memory sub-system. However, as described above the active mitigation measures and/or their control may be entirely dependent on the power state of the memory sub-system. For example, an active cooling component may require the memory sub-system to be connected to the main power supply, receiving power from the main power supply, and/or be powered on in order to provide active cooling of the memory sub-system. Therefore, when the memory sub-system is not connected to the main power supply, receiving power from the main power supply, and/or powered on, the memory sub-system may be unable to mitigate environmental conditions which may cause characteristics of the memory sub-systems to exceed the aforementioned thresholds and cause data loss events.

Many events may lead to the memory sub-system being powered down and/or disconnected from a main power supply. For example, a natural disaster or other interruption to power supply production and transmission may interrupt the supply of power to the memory subsystem. Further, a reduced capacity to service memory sub-systems and/or a reduced need for memory sub-systems may lead to a power down or disconnection event. Furthermore, a cost savings or space constraint may lead to a power down or disconnection event. Regardless of the cause, the memory sub-system that is powered down or disconnected from the main power supply may be facing degradation of its stored data resulting from the lack of power supply and exposure to environmental conditions that it is unable to mitigate due to lack of a main power supply.

Meanwhile, users of the memory sub-system may be unaware of the conditions influencing the memory sub-system it its powered down state. For example, a user may not be cognizant of the environmental conditions in a shut down or partially shut down data center or storage closet where a memory sub-system resides while it is powered down and/or disconnected from the main power supply. A user may, at a later time, reconnect the memory sub-system to a main power supply and/or power the memory sub-system back on and expect the data stored thereupon to be present and have retained its fidelity. However, in some examples the environmental conditions may have cause characteristics of the memory sub-system to exceed a threshold level for a threshold amount of time associated with data loss events. As such, the user may be faced with unexpected and/or catastrophic data loss.

Aspects of the present disclosure address the above and other deficiencies by providing, when delivery of power to a memory sub-system comprising a plurality of non-volatile memory components from a main power supply is interrupted, power from an auxiliary power supply to a portion of a controller interfacing with the non-volatile memory devices. The auxiliary power supply may be utilized to perform, responsive to a prediction that a particular portion of the plurality of non-volatile memory components will experience an impending data loss event generated when the delivery of the power to the memory sub-system from the main power supply is interrupted, a targeted refresh operation on data stored in the particular portion. The targeted refresh operation may be performed utilizing power from an auxiliary power supply which is current limited and/or supplies less power to the memory sub-system than is supplied by the main power supply to the memory sub-system. The targeted refresh operation may proceed on a memory component-by-memory component basis, a die-by-die basis, a page-by-page basis and/or some other progression which only provides limited accesses to a portion of the memory components at a time instead of simultaneously accessing all the memory components with high-speed input and output processing as occurs when utilizing the power supplied from the main power supply. That is, targeted refreshes may utilize limited portions of controllers in the memory sub-system and/or utilize limited portions of the full capacity of such controllers to perform refreshes that are limited in scope as compared to a blanketed refresh which may be performed utilizing power delivered from the main power supply. As such, the targeted refreshes utilizing power delivered from the auxiliary power supply may be limited in scope of data being accessed and/or refreshed at once in order to utilize less power than refreshes performed utilizing the main power supply. Accordingly, the target refreshes may conserve the auxiliary power supply and refresh data most at risk for data loss events.

FIG. 1 illustrates an example computing system 100 that includes a memory subsystem 110 in accordance with some embodiments of the present disclosure. The memory subsystem 110 can include media, such as one or more volatile memory devices (e.g., memory component 140), one or more non-volatile memory components (e.g., memory component 130), or a combination of such.

A memory sub-system 110 can be a storage device, a memory module, or a hybrid of a storage device and memory module. Examples of a storage device include a solid-state drive (SSD), a flash drive, a universal serial bus (USB) flash drive, an embedded Multi-Media Controller (eMMC) drive, a Universal Flash Storage (UFS) drive, a secure digital (SD) card, and a hard disk drive (HDD). Examples of memory modules include a dual in-line memory module (DIMM), a small outline DIMM (SO-DIMM), and various types of non-volatile dual in-line memory modules (NVDIMMs).

The computing system 100 can be a computing device such as a desktop computer, laptop computer, server, network server, mobile device, a vehicle (e.g., airplane, drone, train, automobile, or other conveyance), Internet of Things (IoT) enabled device, embedded computer (e.g., one included in a vehicle, industrial equipment, or a networked commercial device), or such computing device that includes memory and a processing device.

The computing system 100 can include a host system 120 that is coupled to one or more memory sub-systems 110. In some embodiments, the host system 120 is coupled to different types of memory sub-system 110. FIG. 1 illustrates one example of a host system 120 coupled to one memory sub-system 110. As used herein, “coupled to” or “coupled with” generally refers to a connection between components, which can be an indirect communicative connection or direct communicative connection (e.g., without intervening components), whether wired or wireless, including connections such as electrical, optical, magnetic, and the like.

The host system 120 can include a processor chipset and a software stack executed by the processor chipset. The processor chipset can include one or more cores, one or more caches, a memory controller (e.g., an SSD controller), and a storage protocol controller (e.g., PCIe controller, SATA controller). The host system 120 uses the memory sub-system 110, for example, to write data to the memory sub-system 110 and read data from the memory sub-system 110.

The host system 120 can be coupled to the memory sub-system 110 via a physical host interface. Examples of a physical host interface include, but are not limited to, a serial advanced technology attachment (SATA) interface, a peripheral component interconnect express (PCIe) interface, universal serial bus (USB) interface, Fibre Channel, Serial Attached SCSI (SAS), Small Computer System Interface (SCSI), a double data rate (DDR) memory bus, a dual in-line memory module (DIMM) interface (e.g., DIMM socket interface that supports Double Data Rate (DDR)), Open NAND Flash Interface (ONFI), Double Data Rate (DDR), Low Power Double Data Rate (LPDDR), or any other interface. The physical host interface can be used to transmit data between the host system 120 and the memory sub-system 110. The host system 120 can further utilize an NVM Express (NVMe) interface to access components (e.g., memory components 130) when the memory sub-system 110 is coupled with the host system 120 by the PCIe interface. The physical host interface can provide an interface for passing control, address, data, and other signals between the memory sub-system 110 and the host system 120. FIG. 1 illustrates a memory sub-system 110 as an example. In general, the host system 120 can access multiple memory sub-systems via a same communication connection, multiple separate communication connections, and/or a combination of communication connections.

The memory components 130, 140 can include any combination of the different types of non-volatile memory devices and/or volatile memory devices. The volatile memory devices (e.g., memory component 140) can be, but are not limited to, random access memory (RAM), such as dynamic random-access memory (DRAM) and synchronous dynamic random-access memory (SDRAM).

One example of non-volatile memory devices is a negative-and (NAND) memory device (also known as flash technology). A non-volatile memory device may be a package of one or more dice. Each die can consist of one or more planes. Planes can be groups into logic units (LUN). For some types of non-volatile memory devices (e.g., NAND devices), each plane consists of a set of physical blocks. Each block consists of a set of pages. Each page consists of a set of memory cells (“cells”). A cell is an electronic circuit that stores information. A block hereinafter refers to a unit of the memory device used to store data and can include a group of memory cells, a word line group, a word line, or individual memory cells. For some memory devices, blocks (also hereinafter referred to as “memory blocks”) are the smallest area than can be erased. Pages cannot be erased individually, and only whole blocks can be erased.

Each of the memory devices can include one or more arrays of memory cells. Depending on the cell type, a cell can store one or more bits of binary information, and has various logic states that correlate to the number of bits being stored. The logic states can be represented by binary values, such as “0” and “ 1”, or combinations of such values. There are various types of cells, such as single level cells (SLCs), multi-level cells (MLCs), triple level cells (TLCs), and quad-level cells (QLCs). For example, a SLC can store one bit of information and has two logic states.

Some NAND memory devices employ a floating-gate architecture in which memory accesses are controlled based on a relative voltage change between the bit line and the word lines. Other examples of NAND memory devices can employ a replacement-gate architecture that can include the use of word line layouts that can allow for charges corresponding to data values to be trapped within memory cells based on properties of the materials used to construct the word lines.

Some examples of non-volatile memory devices (e.g., memory component 130) include negative-and (NAND) type flash memory and write-in-place memory, such as three-dimensional cross-point (“3D cross-point”) memory device, which is a cross-point array of nonvolatile memory cells. A cross-point array of non-volatile memory can perform bit storage based on a change of bulk resistance, in conjunction with a stackable cross-gridded data access array. Additionally, in contrast to many flash-based memories, cross-point non-volatile memory can perform a write in-place operation, where a non-volatile memory cell can be programmed without the non-volatile memory cell being previously erased. NAND type flash memory includes, for example, two-dimensional NAND (2D NAND) and three-dimensional NAND (3D NAND).

Each of the memory components 130, 140 can include one or more arrays of memory cells. One type of memory cell, for example, single level cells (SLC) can store one bit per cell. Other types of memory cells, such as multi-level cells (MLCs), triple level cells (TLCs), quad-level cells (QLCs), and penta-level cells (PLC) can store multiple bits per cell. In some embodiments, each of the memory components 130 can include one or more arrays of memory cells such as SLCs, MLCs, TLCs, QLCs, or any combination of such. In some embodiments, a particular memory device can include an SLC portion, and an MLC portion, a TLC portion, a QLC portion, or a PLC portion of memory cells. The memory cells of the memory components 130 can be grouped as pages that can refer to a logical unit of the memory device used to store data. With some types of memory (e.g., NAND), pages can be grouped to form blocks.

Although non-volatile memory components such as three-dimensional cross-point arrays of non-volatile memory cells and NAND type memory (e.g., 2D NAND, 3D NAND) are described, the memory component 130 can be based on any other type of non-volatile memory or storage device, such as such as, read-only memory (ROM), phase change memory (PCM), selfselecting memory, other chalcogenide based memories, ferroelectric transistor random-access memory (FeTRAM), ferroelectric random access memory (FeRAM), magneto random access memory (MRAM), Spin Transfer Torque (STT)-MRAM, conductive bridging RAM (CBRAM), resistive random access memory (RRAM), oxide based RRAM (OxRAM), negative-or (NOR) flash memory, and electrically erasable programmable read-only memory (EEPROM).

The memory sub-system may include a memory sub-system controller 115 (or controller 115 for simplicity) which can communicate with the memory components 130 to perform operations such as reading data, writing data, or erasing data at the memory components 130 and other such operations. The memory sub-system controller 115 can include hardware such as one or more integrated circuits and/or discrete components, a buffer memory, or a combination thereof. The hardware can include digital circuitry with dedicated (i.e., hard-coded) logic to perform the operations described herein. The memory sub-system controller 115 can be a microcontroller, special purpose logic circuitry (e.g., a field programmable gate array (FPGA), an application specific integrated circuit (ASIC), etc.), or other suitable processor.

The memory sub-system controller 115 can include a processor 117 (e.g., a processing device) configured to execute instructions stored in a local memory 119. In the illustrated example, the local memory 119 of the memory sub-system controller 115 includes an embedded memory configured to store instructions for performing various processes, operations, logic flows, and routines that control operation of the memory sub-system 110, including handling communications between the memory sub-system 110 and the host system 120.

In some embodiments, the local memory 119 can include memory registers storing memory pointers, fetched data, etc. The local memory 119 can also include read-only memory (ROM) for storing micro-code. While the example memory sub-system 110 in FIG. 1 has been illustrated as including the memory sub-system controller 115, in another embodiment of the present disclosure, a memory sub-system 110 does not include a memory sub-system controller 115, and can instead rely upon external control (e.g., provided by an external host, or by a processor or controller separate from the memory sub-system).

In general, the memory sub-system controller 115 can receive commands or operations from the host system 120 and can convert the commands or operations into instructions or appropriate commands to achieve the desired access to the memory components 130 and/or the memory component 140. The memory sub-system controller 115 can be responsible for other operations such as wear leveling operations, garbage collection operations, error detection and error-correcting code (ECC) operations, encryption operations, caching operations, and address translations between a logical address (e.g., logical block address (LBA), namespace) and a physical address (e.g., physical block address, physical media locations, etc.) that are associated with the memory components 130. The memory sub-system controller 115 can further include host interface circuitry to communicate with the host system 120 via the physical host interface. The host interface circuitry can convert the commands received from the host system into command instructions to access the memory components 130 and/or the memory component 140 as well as convert responses associated with the memory components 130 and/or the memory component 140 into information for the host system 120.

The memory sub-system 110 can also include additional circuitry or components that are not illustrated. In some embodiments, the memory sub-system 110 can include a cache or buffer (e.g., DRAM) and address circuitry (e.g., a row decoder and a column decoder) that can receive an address from the memory sub-system controller 115 and decode the address to access the memory component 130 and/or the memory component 140.

In some embodiments, the memory component 130 includes local media controllers 135 that operate in conjunction with memory sub-system controller 115 to execute operations on one or more memory cells of the memory components 130. An external controller (e.g., memory sub-system controller 115) can externally manage the memory component 130 (e.g., perform media management operations on the memory component 130). In some embodiments, a memory component 130 is a managed memory device, which is a raw memory device combined with a local controller (e.g., local controller 135) for media management within the same memory device package. An example of a managed memory device is a managed NAND (MNAND) device.

The memory sub-system 110 can include a data retention component 113. In some embodiments, the memory sub-system controller 115 includes at least a portion of the data retention component 113. For example, the memory sub-system controller 115 can include a processor 117 (processing device) configured to execute instructions stored in local memory 119 for performing the operations described herein. In some embodiments, the data retention component 113 is part of the host system 110, an application, or an operating system.

For example, the data retention component 113 may include hardware (e.g., various circuitry and/or physical/electrical components) and/or instructions executable by such hardware to accomplish the operations described herein. In such examples, the hardware and/or instructions may be part of and/or integrated partially or fully with the memory sub-system controller 115 and/or its components. In some examples, the data retention component 113 may include non-transitory machine-readable instructions (e.g., stored at and/or executable from local memory 119 executable by processor 117 to accomplish such operations.

However, examples are not so limited. For example, the data retention component 113 may include hardware and/or instructions executable by such hardware that are separate from and/or physically distinct from the memory sub-system controller 115 and/or its components. In such examples, the data retention component may not be part of and/or integrated partially or fully with the memory sub-system controller 115 and/or its components but may be communicatively coupled thereto. For example, the data retention component 113 may be a separate controller (e.g., a microcontroller) that may be at least partially physically and/or functionally separate from the memory sub-system controller 115 but may be communicatively coupled to the memory subsystem controller 115. For example, the data retention component 113 may include a processing device configured to execute instructions stored in local memory for performing the operations described herein, at least a portion of the processing device, the instructions, and/or the local memory being physically distinct and/or remotely located from the components of the memory sub-system controller 115.

Although not shown in FIG. 1 so as to not obfuscate the drawings, the data retention component 113 may include and/or be communicatively coupled to various circuitry to facilitate monitoring a characteristic of the memory sub-system 110. The monitored characteristic may include a characteristic of the memory sub-system 110 and/or its components (e.g., non-volatile memory component 130) associated with data retention at the memory sub-system 110 and/or at a specific component (e.g., non-volatile memory component 130) of the memory sub-system 110. Some examples of monitored characteristics which may be associated with data retention include a temperature of the memory sub-system 110 and/or its components, a duration spent at those temperatures, whether power is being delivered from the main power supply to the memory subsystem 110 and/or its components, a duration of an interruption to the delivery of power from the main power supply to the memory sub-system 110 and/or its components. For example, the data retention component 113 may include and/or be communicatively coupled to various circuitry to facilitate monitoring of a temperature (e.g., a temperature sensor) of the memory sub-system 110, a duration of time that the memory sub-system 110 spent at the monitored temperature, whether power is being delivered from the main power supply to the memory sub-system 110, a duration of an interruption of delivery of power from a power supply to the memory sub-system 110, etc. In some examples, the various circuitry (e.g., temperature sensor, duration sensor, power supply sensor, etc.) to facilitate monitoring of a temperature, temperature duration, and/or duration of power supply removal specifically of the non-volatile memory component 130 may report and/or make available for retrieval its measurements to the data retention component 113 directly and/or may write its measurements to a data repository commonly accessible by the data retention component 113 and/or the sensor.

In some examples, the data retention component 113 may include various circuitry utilizable, when delivery of power from a power supply (e.g., a main and/or primary power supply) to the memory sub-system 110 is interrupted. An interruption of power delivery from a main power supply may include a temporary or permanent reduction or elimination of power provided from the main power supply to the memory sub-system 110 and/or its components. For example, an interruption of power delivery from the main power supply may include a disruption and/or discontinuation of power delivery from a 12V main power supply to a memory sub-system 110 and/or its components across a main power rail of the memory sub-system 110.

An interruption of the delivery of power from the main power supply may include an instance when a main power supply is decoupled (e.g., unplugged) or otherwise removed from the memory sub-system 110. An interruption of the delivery of power from the main power supply may include an instance when a main power supply remains coupled to the memory sub-system 110 but power is no longer being delivered from the main power supply to the memory subsystem 110. An interruption of the delivery of power from the main power supply may include an instance where the memory sub-system 110 is switched into an off state or a sleep state. An interruption of the delivery of power from the main power supply may include an instance when a connection to the main power supply is damaged. An interruption of the delivery of power from the main power supply may include an instance when a power outage, a blackout, a brown out, a blown fuse, a tripped circuit breaker, etc. disrupts the flow of power from a main power source to the memory sub-system 110. An interruption of the delivery of power from the main power supply may include an instance when a main power supply is exhausted and/or has no or not enough power to deliver to the memory sub-system 110 to render it fully operational.

The data retention component 113 may include various circuitry utilizable, when delivery of power from a power supply (e.g., a main and/or primary power supply) to the memory sub-system 110 is interrupted, to facilitate monitoring the characteristic of the memory subsystem 110 associated with data retention at a non-volatile memory component 130 of the memory subsystem 105. For example, the data retention component 113 can include circuitry and/or special purpose circuitry in the form of an ASIC, FPGA, state machine, and/or other logic circuitry that can orchestrate and/or perform operations (e.g., utilizing power provided from an auxiliary or secondary power supply, a reserve of power stored in a battery or capacitor, etc.) in the absence of and/or without power from the main power supply to monitor the characteristic of the memory subsystem 110 and/or its components.

In some examples, the data retention component 113 may be operated in the absence of and/or without power from the main power supply to monitor to monitor a temperature of the memory sub-system 110, a duration of time over which the memory sub-system 110 was exposed to and/or remained at that temperature, whether the memory sub-system 110 is receiving power from a main power supply, and/or a duration of an interruption of power delivery from a main power supply to the memory sub-system 110.

In some examples, the data retention component 113 may be operated in the absence of and/or without power from the main power supply in order to monitor such characteristics as they relate to specific components and/or groups of components of the memory sub-system 110. For example, the data retention component 113 may be operated in the absence of and/or without power from the power supply to monitor a temperature of a specific non-volatile memory component 130 and/or a group of non-volatile memory components 130, a duration of time that the specific non-volatile memory component 130 and/or a group of non-volatile memory components 130 is exposed to a particular temperature and/or range of temperatures, whether the specific non-volatile memory component 130 and/or a group of non-volatile memory components 130 is receiving power from a main power supply, and/or a duration of time that the receipt of power from the main power supply to the specific non-volatile memory component 130 and/or a group of non-volatile memory components 130 is interrupted. In some examples, the data retention component 113 may be operated in the absence of and/or without power from the main power supply to monitor a temperature, a duration of time exposed to temperature, whether power delivery from a main power supply has been interrupted, and/or a duration of time a main power supply has been interrupted for particular portions of the non-volatile memory component 130 such as particular memory die, planes, blocks, pages and/or groups thereof.

The data retention component 113 may be utilized, when delivery of power from a power supply to the memory sub-system 110 is interrupted, to predict, based on the monitored characteristic, an impending data loss event for the non-volatile memory component 130. A data loss event may include an instance when an original data value stored on the non-volatile memory component 130 is lost, modify, degraded, and/or otherwise rendered unreadable as the original data value. The data loss event may include instances where the original data value is readable as a different data value from the original value and/or instances where the original data value is no longer readable. For example, the data loss event may include instances where the stored data value is erroneous with respect to its original value and/or instances where a stored data value is absent.

An impending data loss event may include a data loss event that has happened, is going to happen, is projected to happen if conditions (e.g., the monitored characteristic) remain the same, is trending toward happening under the monitored characteristic, has exceeded or will exceed a probability threshold of happening, etc. For example, an impending data loss event may include a data loss event that has a likelihood of occurring that is above a certain threshold unless the currently monitored conditions are altered (e.g., power is restored to the memory sub-system 110, the temperature of the non-volatile memory component 130 is reduced, etc.).

The likelihood of a data loss event and/or a determination of whether it is impending may be based on physical properties, capabilities, and/or manufacturer specifications for the memory sub-system 110 and/or the non-volatile memory component 130. For example, a specification may exist for the memory sub-system 110 and/or the non-volatile memory component 130 of the memory subsystem 110 which specifies a relationship between an amount of time that power delivery from a power supply to the memory sub-system 110 is interrupted and an amount and/or likelihood of expected data loss events for the memory sub-system 110 and/or the non-volatile memory component 130 of the memory subsystem 110. Such a specification may be utilized to identify threshold value amounts of time that, when power delivery from a power supply is interrupted over, predict or indicate an impending data loss event will occur.

Likewise, a specification may exist for the memory sub-system 110 and/or the nonvolatile memory component 130 of the memory subsystem 110 which specifies a relationship between a temperature of the memory sub-system 110 and/or the non-volatile memory component 130 and an amount and/or likelihood of expected data loss events for the memory sub-system 110 and/or the non-volatile memory component 130 of the memory subsystem 110. Further, the specification may specify a relationship between a time at the temperature for the memory subsystem 110 and/or the non-volatile memory component 130 and an amount and/or likelihood of expected data loss events for the memory sub-system 110 and/or the non-volatile memory component 130 of the memory subsystem 110. Such a specification may be utilized to identify threshold value temperatures and/or amounts of time at those temperatures that, when delivery of power from a power supply is interrupted over, predict or indicate an impending data loss event.

In some examples, an error rate associated with stored data values may be utilized to identify threshold error rate values that, when power delivery from a main power supply is interrupted, predict or indicate an impending data loss event. For example, a raw bit error rate (RBER) associated with the memory sub-system 110 and/or the non-volatile memory component 130 may signify an impending data loss event when the RBER exceeds a threshold error rate value defined by an error correction capability of an ECC component of the memory sub-system 110.

As such, the data retention component 113 may be utilized, when delivery of power from a main power supply to the memory sub-system 110 is interrupted and/or in the absence of and/or without utilizing power from the main power supply, to predict, based on the monitored characteristic, an impending data loss event for the non-volatile memory component 130 by comparing the monitored characteristic to a threshold value of the monitored characteristic associated with the data loss event such as those threshold levels described above. For example, the data retention component 113 may predict an impending data loss event for the non-volatile memory component 130 by comparing a duration of an interruption of the delivery of power from the main power supply to the memory sub-system 110 and/or the non-volatile memory component 130 to threshold value amounts of time that, when delivery of power from a main power supply is interrupted over, is predicted of an impending data loss event. In some examples, the data retention component 113 may predict an impending data loss event for the non-volatile memory component 130 by comparing a temperature and/or a time at a temperature for the memory subsystem 110 and/or the non-volatile memory component 130 to the threshold value temperature and/or time at temperature amounts that, occurring during an interruption of the delivery of power from the main power supply, is predictive of an impending data loss event. In some examples, the data retention component 113 may predict an impending data loss event for the non-volatile memory component 130 by comparing an error rate for the memory sub-system 110 and/or the non-volatile memory component 130 to the threshold amount of error correction capability by an ECC component predictive of an impending data loss event. The prediction of an impending data loss event may be generated at the time one of the above-described monitored characteristics exceeds a threshold value marking conditions associated with data loss. Additionally, the prediction of an impending data loss event may be generated when one of the above-described monitored characteristics is projected to exceed a threshold value in the future based on, for example, an extrapolation of a trend of the monitored characteristic.

In addition, the data retention component 113 may be utilized, when delivery of power to the memory sub-system 110 from the main power supply is interrupted, to generate a data loss warning. For example, the memory sub-system 110 may generate the data loss warning by generating a signal transmitted to and/or retrieved by a host 120. The signal may instigate, by the host 120, a communication and/or a display of the data loss warning to a user and/or administrator of the memory sub-system 110. For example, the memory sub-system 110 may send a signal to the host 120 responsive to the prediction of an impending data loss event for the non-volatile memory component 130. In response to receiving the signal, the host 120 may generate and/or cause the communication of the data loss warning to a monitoring user and/or application. For example, the data loss warning may include an alert such as an email, a text message, a telephone call, etc. Additionally, or alternatively, the data loss warning may include an alert such as an auditory warning. For example, the data loss warning may include a beep, buzz, chirp, etc. generated by a speaker, piezo electric buzzer, etc. Additionally, or alternatively, the data loss warning may include an alert such as a visual warning. For example, the data loss warning may include causing a light to emit light, causing a light to cease emitting light, causing a light to flash, causing a light to flash a particular pattern, etc. The data loss warning may be a signal to a human user to communicate that a data loss event is impending and to spur the user to intervene such as by restoring the power to the memory sub-system 110.

The data retention component 113 may generate the data loss warning responsive to predicting the impending data loss event. For example, when the monitored characteristic has reached, is projected to reach, exceeds, is projected to exceed, etc. its associated threshold value, the data retention component 113 may generate the data loss warning.

The data retention component 113 may be utilized, when delivery of power to the memory sub-system 110 from a main power supply is interrupted, to persist the data loss warning for a period of time. As such, the data loss warning may be initiated and persisted in the absence of power from the main power supply. For example, the data retention component 113 may persist the data loss warning until the delivery of power from the main power supply to the memory sub-system 110 is restored. The data retention component 113 may persist the data loss warning until an auxiliary power source, powering the data retention component 113 while the primary power supply is interrupted, is exhausted. For example, the data loss warning may be persisted until an auxiliary power reservoir such as a battery or capacitor has its charge depleted.

In some examples, the data retention component 113 may be utilized, when delivery of power from a main power supply to the memory sub-system 110 is interrupted, to determine, based on the monitored characteristic, whether a data retention limit threshold has been reached for the memory sub-system 110 and/or the non-volatile memory component 130. That is, the data retention component 113 may be utilized to determine, based on the monitored characteristic, whether a data retention limit threshold has been reached for the memory sub-system 110 and/or the non-volatile memory component 130 in the absence of power from the main power supply. For example, the data retention limit threshold may include a threshold value of the monitored characteristic which represents a limit amount of the threshold characteristic past which the data loss event is projected to be inevitable and/or uncorrectable. In such examples, the data retention component 113 may be utilized, when delivery of power from a main power supply to the memory sub-system 110 is interrupted, to persist the data loss warning until the data retention limit threshold is determined to have been reached. That is, the data retention component 113 may be utilized to persist the data loss warning until the data retention limit threshold is determined to have been reached, all in the absence of power being delivered from the main power supply. In some examples, once the data retention limit threshold is determined to have been reached a new or different warning may be generated by the data retention component 113 which signifies that a data loss event has likely already occurred at the memory sub-system 110 and/or the non-volatile memory component 130. For example, once the data loss event has likely already occurred, the data retention component 113 may write a message to non-volatile memory warning that the data loss event may have occurred.

In this manner, the data retention component 113 may operate in the absence of power from the main power supply. For example, the data retention component may monitor the memory sub-system 110 for conditions indicative of an impending data loss event, predict such impending data loss events, and/or manage warning users of the data loss events so that they can manually intervene to mitigate and/or prevent data loss in non-volatile memory components 130, all without utilizing power from the main power supply. That is, the data retention component 113 may perform the functionalities described throughout during the interruption of power delivery from the main power supply.

For example, the data retention component 113 may include various circuitry utilizable, when delivery of power from a main power supply to the memory sub-system 110 is interrupted, to perform a targeted refresh operation on data stored in a particular non-volatile memory component 130 of a plurality of non-volatile memory devices and/or on data stored in a particular portion of a non-volatile memory component 130. As described above, a prediction that a particular portion of the plurality of non-volatile memory components will experience an impending data loss event may be generated in the absence of power delivery from the main power supply. Responsive to this prediction, the data retention component 113 may perform a targeted refresh operation on data stored in the particular portion during the interruption to the delivery of power from the main power supply to the memory sub-system. That is, the data retention component 113 may perform targeted refreshes in the absence of and/or without power from the main power supply.

For example, the data retention component 113 may operate in the absence of power from the main power supply (e.g., utilizing an auxiliary power supply instead) to systematically and/or selectively refresh particular portions of data among the data stored at the non-volatile memory component 130 prior to any data loss actually occurring. In some examples, the data retention component 113 may operate while delivery of power from the main power supply is interrupted (e.g., utilizing power from an auxiliary power supply instead) to selectively refresh data at, for example, a greatest risk of being lost or degraded in a predicted data loss event. In some examples, the data retention component 113 may operate while delivery of power from the main power supply is interrupted (e.g., utilizing power from an auxiliary power supply instead) to selectively refresh data designated as having a highest priority stored in a portion of a non-volatile memory component 130 exposed to conditions associated with a data loss event.

The data retention component 113 may continue to perform the targeted refreshing of data until delivery of power from a main power supply to the memory sub-system 110, the memory sub-system controller 115, and/or the non-volatile memory component 130 is restored and/or until power reservoir of an auxiliary power supply is exhausted. In some examples, the data retention component 113 may perform a blanket refreshing of data stored in a non-volatile memory component 130 exposed to conditions associated with a data loss event until delivery of power from a main power supply is restored and/or until an auxiliary power supply is exhausted. For example, the data retention component 113 may perform a systematic refresh of substantially all the data exposed to conditions associated with a data loss event until delivery of power from a main power supply is restored and/or until an auxiliary power supply is exhausted (e.g., systematically targeting smaller portions of the data stored at the non-volatile memory component 130 to be refreshed at a time eventually resulting in substantially all the data being refreshed unless delivery of power from a main power supply is restored or an auxiliary power supply is exhausted).

The data retention component 113 may, in some examples, utilize data from the memory sub-system controller 115 about which die in a non-volatile memory component 130 exposed to conditions associated with a data loss event are at most risk for data retention related failures and can target the refreshed accordingly until a main power supply is restored to the memory sub-system 110 and/or until an auxiliary power supply is exhausted. In some examples, a memory sub-system controller 115 may store information regarding when data was written to particular pages and/or dies and how long it has been since that data was last refreshed. This data may be utilized by the data retention component 113 to identify which data should be targeted and/or targeted first for refreshing in a refresh operation.

The data retention component 113 may, in some examples, utilize and/or cause an interface (e.g., a NAND interface) between the memory sub-system controller 115 and the nonvolatile memory component 130 to address the non-volatile memory component 130 die by die and refresh the data. Since the data retention component 113 may be performing the refresh operations in the absence of the main power supply, the power to operate the data retention component 113 and/or to perform the data refresh operations with the memory sub-system controller 115 may be supplied from an auxiliary power supply.

In some examples, the data retention component 113 may, as described above, produce a data loss warning. The data retention component 113 may persist the data loss warning until a threshold amount of time and/or a threshold amount of auxiliary power supply consumption has occurred. At that point, the data retention component 113 may begin the targeted refresh operations. As such, the data retention component 113 may, responsive to predicting an imminent data loss event, first try to recruit help and/or spur an intervention by signaling the data loss event by the data loss warning. After the threshold amount of time has passed with the data loss signal being unanswered (e.g., no intervention occurring) the data retention component 113 may then attempt to save as much data and/or a much critical data as it can by performing targeted refreshes until an auxiliary power supply is exhausted.

For example, the memory sub-system 110 may include a plurality of non-volatile memory components 130 and/or a processing device such as the data retention component 113 and/or the memory sub-system controller 115. The processing device may be configured to operate, utilizing an auxiliary power supply in an absence of power from a main power supply to trigger and/or perform targeted data refreshes. In an example, the processing device may be configured to identify a portion of the plurality of non-volatile memory components at risk of data retention failures. The processor may be configured to identify the portion of the plurality of non-volatile memory components at the risk of the data retention failures based on a comparison of a monitored temperature of the plurality of non-volatile memory components and a monitored amount of time since the delivery of power from the main power supply was interrupted to a threshold level indicative of an impending data loss event.

The processing device may be configured to cause a controller (e.g., memory subsystem controller 115, operating in a reduced capacity utilizing an auxiliary power supply in the absence of the power from the main power supply, to address the portion of the plurality of nonvolatile memory components identified as at risk of data retention failures on a per memory component basis to refresh data at risk of loss. Refreshing the data at risk of loss may be performed by reading the data values out of the portion of the plurality of non-volatile memory components and writing it back to the plurality of non-volatile memory components.

FIG. 2 illustrates an example of a computing system 200 that includes a memory subsystem 210 in accordance with some embodiments of the present disclosure. The system 200 may be a computing system including many elements illustrated in the system 100 FIG. 1 having same and/or similar functions with distinctions therebetween explained below.

The computing system 200 may include a memory sub-system 210. The memory subsystem can include media, such as one or more volatile memory devices (e.g., memory component 240), one or more non-volatile memory components (e.g., memory component 230), or a combination of such. The computing system 200 can include a host system 220 that is coupled to one or more memory sub-systems 210.

The memory components 230, 240 can include any combination of the different types of non-volatile memory devices and/or volatile memory devices. In some examples, memory component 240 may include volatile memory devices and memory component 230 may include non-volatile memory components 230.

The memory sub-system may include a memory sub-system controller 215 (or controller 215 for simplicity) which can communicate with the memory components 230 to perform operations such as reading data, writing data, or erasing data at the memory components 230 and other such operations.

The memory sub-system controller 215 can include a processor 217 (e.g., a processing device) configured to execute instructions stored in a local memory 219. In the illustrated example, the local memory 219 of the memory sub-system controller 215 includes an embedded memory configured to store instructions for performing various processes, operations, logic flows, and routines that control operation of the memory sub-system 210, including handling communications between the memory sub-system 210 and the host system 220.

The memory sub-system controller 215 may include a back-end component that interfaces with non-volatile memory component 230. The interface may, when fully enabled (e.g., in an on state and supplied with its full operational power requirement such as 12 volts from a primary power rail supplied from the main power supply 242), allow the controller to interface with the non-volatile memory component 230 and with the host at high speed. The interface, when fully enabled, may process inputs and/or out puts to and/or from the host and the nonvolatile memory component 230. The interface may, when fully enabled, manage many nonvolatile memory component 230 die in parallel to maintain maximum performance with the host.

In some embodiments, the local memory 219 can include memory registers storing memory pointers, fetched data, etc. The local memory 219 can also include read-only memory (ROM) for storing micro-code. While the example memory sub-system 110 in FIG. 2 has been illustrated as including the memory sub-system controller 215, in another embodiment of the present disclosure, a memory sub-system 210 does not include a memory sub-system controller 215, and can instead rely upon external control (e.g., provided by an external host, or by a processor or controller separate from the memory sub-system).

In general, the memory sub-system controller 215 can receive commands or operations from the host system 220 and can convert the commands or operations into instructions or appropriate commands to achieve the desired access to the memory component 230 (e.g., utilizing the interface component) and/or the memory component 240. The memory sub-system controller 215 can be responsible for other operations such as wear leveling operations, garbage collection operations, error detection and error-correcting code (ECC) operations, encryption operations, caching operations, and address translations between a logical address (e.g., logical block address (LBA), namespace) and a physical address (e.g., physical block address, physical media locations, etc.) that are associated with the memory components 230. The memory sub-system controller 215 can further include host interface circuitry to communicate with the host system 220 via the physical host interface. The host interface circuitry can convert the commands received from the host system into command instructions to access the memory component 230 (e.g., utilizing the interface component) and/or the memory component 240 as well as convert responses associated with the memory component 230 and/or the memory component 240 into information for the host system 220.

The memory sub-system 210 can also include additional circuitry or components that are not illustrated. In some embodiments, the memory sub-system 210 can include a cache or buffer (e.g., DRAM) and address circuitry (e.g., a row decoder and a column decoder) that can receive an address from the memory sub-system controller 115 and decode the address to access the memory component 230 and/or the memory component 240.

In some embodiments, the memory component 230 includes local media controllers 235 that operate in conjunction with memory sub-system controller 215 to execute operations on one or more memory cells of the memory components 230. An external controller (e.g., memory sub-system controller 215) can externally manage the memory component 230 (e.g., perform media management operations on the memory component 230). In some embodiments, a memory component 230 is a managed memory component, which is a raw memory device combined with a local controller (e.g., local controller 235) for media management within the same memory device package. An example of a managed memory device is a managed NAND (MNAND) device

The memory sub-system 110 can include a data retention component 213. The data retention component 213 can be a component such as data retention component 113 described in FIG. 1 and perform all the same functions. In the non-limiting example illustrated in FIG. 2 the data retention component may include hardware and/or instructions executable by such hardware that are separate from and/or physically distinct from the memory sub-system controller 215. For example, the data retention component 213 may not be part of and/or integrated partially or fully with the memory sub-system controller 215 and/or its components but may be communicatively coupled thereto. For example, the data retention component 213 may be a separate controller (e.g., a microcontroller) that may be at least partially physically and/or functionally separate from the memory sub-system controller 215 and/or its processing device but may be communicatively coupled to the memory sub-system controller 215. For example, the data retention component 213 may include a processing device configured to execute instructions stored in local memory for performing the operations described herein, at least a portion of the processing device, the instructions, and/or the local memory being physically distinct and/or remotely located from the components of the memory sub-system controller 215.

The data retention component 213 may include and/or be communicatively coupled to various circuitry to facilitate monitoring a characteristic of the memory sub-system 210. For example, the data retention component 213 may include or be communicatively coupled to a characteristic sensor 214. A characteristic sensor 214 may include a device configured to monitor a characteristic of the memory sub-system 210 and/or its components (e.g., non-volatile memory component 230). In some examples, the characteristic sensor 214 may be configured to monitor a characteristic of the entire memory sub-system 210 and/or a characteristic of a portion of the memory sub-system 210. For example, the characteristic sensor may be configured to monitor a characteristic of the non-volatile memory component 230 of the memory sub-system 210 utilizing measurements of the characteristic for the entire memory sub-system 210, a portion of the memory sub-system 210 (e.g., measurements specific to the non-volatile memory component 230), and/or sub-portions of a portion of the memory sub-system 210 (e.g., measurements specific to particular dies, planes, blocks, cells, etc. of the non-volatile memory component 230).

The monitored characteristic may include a characteristic of the memory sub-system 210 and/or its components (e.g., non-volatile memory component 230) associated with data retention at the memory sub-system 210 and/or at a specific component (e.g., non-volatile memory component 230) of the memory sub-system 210. For example, the data retention component 213 may include and/or be communicatively coupled to various circuitry to: facilitate monitoring of a temperature (e.g., a temperature sensor) of the memory sub-system 210, a portion of the memory sub-system 210, and/or a sub-portion of the memory sub-system 210; facilitate monitoring a duration of time that the memory sub-system 210, a portion of the memory sub-system 210, and/or a sub-portion of the memory sub-system 210 spent at the monitored temperature; facilitate monitoring a duration of an interruption of the delivery of power from a main power supply to the memory sub-system 210, a portion of the memory sub-system 210, and/or a sub-portion of the memory sub-system 210; etc.. In some examples, the characteristic sensor 214 (e.g., temperature sensor, duration sensor, power supply sensor, etc.) may be configured to monitor temperature, temperature duration, and/or duration of main power supply interruption of a specific plurality of non-volatile memory components, a specific non-volatile memory component 230 of a plurality of non-volatile memory component, a specific die of a non-volatile memory component 230, a specific location where a specific page of data is stored on a non-volatile memory component 230, etc. The characteristic sensor 214 may report and/or make available for retrieval its measurements to the data retention component 213 directly and/or may write its measurements to a data repository commonly accessible by the data retention component 213 and/or the characteristic sensor 214.

The memory sub-system 210 may utilize power to operate. For example, the memory sub-system controller 215, the processor 217, the local memory 219, the non-volatile memory component 230, the local media controller 235, the memory component 240, the characteristic sensor 214, and/or the data retention component 213 may consume electricity in order to perform their various functions. The memory sub-system 210 may include additional components, not illustrated in FIG. 2 , which may also utilize power to operate. For example, the memory subsystem 210 may include active cooling measures which consume electricity to cool the memory sub-system 210 and/or its various components. For example, the memory sub-system 210 may include cooling fans and/or cooling liquid circulation pumps which consume electricity to cool the memory sub-system 210 and/or its various components. These active cooling measures may function to keep components of the memory sub-system 210, such as the non-volatile memory component 230 and others, from reaching and/or sustaining a temperature and/or duration at that temperature associated with potential data damage, degradation, and/or loss.

Many of the components of the memory sub-system 210 may rely on power provided from a main power supply 242. As such, a main power supply 242 may be coupled to and/or provide power to the memory sub-system 210. The main power supply 242 may include a 12 Volt (V) power supply. For example, the memory sub-system 210 may be physical attached (e.g., via a power cord, backplane, power bus, etc.) to a main power supply 242 such as an outlet connected to an electrical power transmission grid. The main power supply 242 may be utilized to operate the components of the memory sub-system 210 while the device is powered on and receiving its full allocation of power from the connected main power supply 242.

For example, when the memory sub-system 210 is connected to the main power supply 242 and is in a fully on, fully operational, non-sleep, and/or non-off state, the memory sub-system 210 may utilize the main power supply 242 to power its components in order to execute their functions. For example, when the memory sub-system 210 is on and connected to the main power supply 242, the main power supply 242 may provide power to the memory sub-system controller 215, the memory component 240, the non-volatile memory component 230, any active colling measures, etc. As such, the memory sub-system may be under a full allocation (e.g., 12 Volts) of power from the main power supply 242 during active operation which may be provided through a primary power rail to operate the memory sub-system controller 215 and/or the nonvolatile memory component 230. The main power supply 242 may provide the full power allocation which may be utilized for operating active cooling measures, interfacing with the host system 220 at high speeds, processing inputs/outputs (I/Os) to/from the host 220, and managing/performing accesses of multiple memory dies of the non-volatile memory component 230 in parallel to maintain its maximum performance capabilities with respect to the host system 220. In some examples, power from the main power supply 242 may be supplied to a regulator 248. The regulator 248 may regulate the voltage supplied by the main power supply 242 to a lower voltage level to be utilized by the non-volatile memory component 230.

The data retention component 213 and/or the characteristic sensor 214 utilized by the data retention component 213 may or may not operate while the memory sub-system 210 is fully on, fully operational, non-sleep, and/or non-off state, the memory sub-system 210. That is, the data retention component 213 and/or the characteristic sensor 214 utilized by the data retention component 213 may or may not receive and/or utilize power from the main power supply 242 in order to operate while the memory sub-system 210 is fully on, fully operational, non-sleep state, and/or non-off state, the memory sub-system 210. In some examples, the data retention component 213 and/or the characteristic sensor 214 utilized by the data retention component 213 may not operate and/or utilize any power while the memory sub-system 210 is fully on, fully operational, non-sleep, and/or non-off state, the memory sub-system 210.

The data retention component 213 and/or the characteristic sensor 214 utilized by the data retention component 213 may be operational in the absence of power from the main power supply 242. For example, when the memory sub-system 210 is disconnected (e.g., unplugged) from the main power supply 242, when the flow of power from the main power supply 242 is interrupted, when the memory sub-system 210 is in an off state, when the memory sub-system 210 is not fully operational, when the memory sub-system 210 is in a sleep state, when the memory sub-system 210 is an off state, etc. the data retention component 213 and/or the characteristic sensor 214 utilized by the data retention component 213 may be operational. In the absence of the primary power supply 242, the memory sub-system controller 215 and/or processor 217 may not be operational and/or the firmware of the memory sub-system 210 may not be executing. In the absence of the primary power supply 242, the data retention component 213 and/or the characteristic sensor 214 may utilize power supplied from an auxiliary power supply 246 to operate.

An auxiliary power supply 246 may include a power supply that is not the main power supply 242. The auxiliary power supply 246 may include a secondary power reservoir such as a battery, a super capacitor, a low voltage power supply, a current limited power supply relative to the primary power supply, etc. The auxiliary power supply 246 may be configured to store and/or supply less power than the primary power supply 242. For example, the auxiliary power supply 246 may include a 3.3 V power supply.

In some examples, the auxiliary power supply 246 may be a same auxiliary power supply utilized to provide power to other components of the memory sub-system 210 in the absence of power from the main power supply 242. For example, the auxiliary power supply 246 may be a same auxiliary power supply utilized to provide power to an EEPROM components of the memory sub-system 210 to operate in the absence of power from the main power supply 242.

The auxiliary power supply 246 may supply power (e.g., 3.3 V) to the data retention component 213 and/or the characteristic sensor 214 utilized by the data retention component 213 to perform its operations. In some examples, the auxiliary power supply 246 may supply its voltage (e.g., 3.3 V) to a regulator 248. The regulator 248 may regulate the data retention component 213 and/or the characteristic sensor 214 utilized by the data retention component 213. In other examples, the auxiliary power supply 246 may supply voltage to the data retention component 213 and/or the characteristic sensor 214 utilized by the data retention component 213 directly to perform its operations. For example, the auxiliary power supply 246 may supply voltage to the data retention component 213 and/or the characteristic sensor 214 utilized by the data retention component 213 via an auxiliary power supply rail.

The auxiliary power supply 246 may include a power supply that begins to supply power to the data retention component 213 and/or the characteristic sensor 214 utilized by the data retention component 213 at the time of and/or in response to the removal and/or interruption of the main power supply 242. In some examples, the auxiliary power supply 246 may utilize the main power supply 242 to charge and/or refill its power reserve capacity when the main power supply 242 is connected, operable, and providing power to the memory sub-system 210 and, when the main power supply 242 is absent the auxiliary power supply 246 may begin to supply power from its reservoir.

The auxiliary power supply 246 may continue to supply power to operate the data retention component 213 and/or the characteristic sensor 214 utilized by the data retention component 213 until the main power supply 242 is restored. As such, the auxiliary power supply 246 may be configured to operate to supply power to the data retention component 213 and/or the characteristic sensor 214 in the absence of the main power supply 242 until the main power supply 242 is restored and/or until the auxiliary power supply is depleted.

As such, the characteristic sensor 214 utilized by the data retention component 213 may operate in the absence of power from the main power supply 242 to continuously and/or periodically monitor a characteristic of the non-volatile memory components 230 without power from the main power supply 242. For example, the characteristic sensor 214 utilized by the data retention component 213 may continuously and/or periodically monitor a characteristic of the nonvolatile memory components 230 while no power is provided from the main power supply 242 to the memory sub-system 210. Therefore, the characteristic sensor 214 utilized by the data retention component 213 may continuously and/or periodically monitor a characteristic of the nonvolatile memory components 230 while the non-volatile memory component 230 is not operational and/or supplied with power from the main power supply 242. Additionally, the characteristic sensor 214 utilized by the data retention component 213 may continuously and/or periodically monitor a characteristic of the non-volatile memory components 230 while the memory subsystem controller 215 is not operational and/or supplied with power from the main power supply 242. Further, the characteristic sensor 214 utilized by the data retention component 213 may continuously and/or periodically monitor a characteristic of the non-volatile memory components 230 while any active cooling measures are not operational and/or supplied with power from the main power supply 242. Additionally, the characteristic sensor 214 utilized by the data retention component 213 may continuously and/or periodically monitor a characteristic of the nonvolatile memory components 230 while the firmware of the memory sub-system 210 is not being executed.

Further, the data retention component 213 may operate in the absence of power from the main power supply 242 to receive, retrieve, and/or utilize the sensed characteristic of the nonvolatile memory components 230 without utilizing power from the main power supply 242. For example, data retention component 213 may operate in the absence of power from the main power supply 242 to receive, retrieve, and/or utilize the sensed characteristic of the non-volatile memory components 230 while no power is provided from the main power supply 242 to the memory subsystem 210. Therefore, data retention component 213 may operate in the absence of power from the main power supply 242 to receive, retrieve, and/or utilize the sensed characteristic of the nonvolatile memory components 230 while the non-volatile memory component 230 is not operational and/or supplied with power from the main power supply 242. Additionally, data retention component 213 may operate in the absence of power from the main power supply 242 to receive, retrieve, and/or utilize the sensed characteristic of the non-volatile memory components 230 while the memory subsystem controller 215 is not operational and/or supplied with power from the main power supply 242. Further, the data retention component 213 may operate in the absence of power from the main power supply 242 to receive, retrieve, and/or utilize the sensed characteristic of the non-volatile memory components 230 while any active cooling measures are not operational and/or supplied with power from the main power supply 242. Additionally, the data retention component 213 may operate in the absence of power from the main power supply 242 to receive, retrieve, and/or utilize the sensed characteristic of the non-volatile memory components 230 while the firmware of the memory sub-system 210 is not being executed.

In this manner, a characteristic of a memory sub-system 210 may be monitored and/or analyzed in the absence of power from a main power supply 242. For example, the characteristic sensor 214 may include a temperature sensor. The temperature sensor may be configured to sense the temperature of the memory sub-system 210, an environment that the memory subsystem resides in, a temperature of each of multiple non-volatile memory components, etc. and/or the duration of the temperature in the absence of power from the main power supply 242. The characteristic sensor 214 may include a power supply sensor. The power supply sensor may be configured to sense when the main power supply 242 is absent from a memory sub-system 210 and/or the amount of time over which the main power supply 242 has been absent from the memory sub-system 210 in the absence of power from the main power supply 242.

The data retention component 213 may be configured to operate, in the absence of power from the main power supply 242, utilizing an auxiliary power supply 246. The data retention component 213 may be configured to operate, in the absence of power from the main power supply 242, to monitor a characteristic of one or more of multiple non-volatile memory components 230. For example, the data retention component 213 may be configured to monitor data from a characteristic sensor 214. The data retention component 213 may be configured to monitor, for example, a temperature of one or more non-volatile memory components 230 and an amount of time since the power delivery from the main power supply to the memory sub-system 210 was interrupted. For example, the data retention component 213 may be configured to monitor these characteristics utilizing temperature data collected by a temperature sensor and/or utilizing power supply data collected by a power supply monitoring sensor.

The data retention component 213 may be configured to operate, in the absence of power from the main power supply 242, to predict, based on the monitored characteristic, an impending data loss event for one or more of the multiple non-volatile memory components 230. For example, the data retention component 213 may be configured to compare, in the absence of power from the main power supply 242, the monitored characteristic (e.g., a monitored temperature, a monitored amount of time at a temperature, a monitored duration of an interruption of power delivery from the main power supply 242, etc.) to a threshold level of the characteristic indicative of an impending data loss event for the non-volatile memory components 230.

As described above, the electrical charge stored in the non-volatile memory component 230 degrades over time. In addition, the charge may degrade much faster at higher temperatures over extended period of times. In some examples, the charge degradation may increase exponentially as temperature rises. Since the stored charge is indicative of the data stored at the non-volatile memory component 230, charge degradation may equate to data degradation. Once enough data degradation has occurred, a data loss event may occur.

The data retention component 213 may be configured to generate, in the absence of power from the main power supply 242, a data loss warning signal to signal the predicted impending data loss event. For example, in response to the monitored characteristic meeting and/or exceeding the threshold level indicative of a data loss event, the data retention component 213 may generate a data loss warning. For example, responsive to a monitored temperature of one or more of multiple non-volatile memory components 230 and/or an elapsed time of a main power supply power delivery interruption meeting or exceeding a threshold temperature, time at temperature, elapsed time without main power supply power delivery, etc. associated with causing a bit error rate of the non-volatile memory component 230 that exceeds the ECC capacity of the memory sub-system 210, the data retention component may generate a warning

For example, a memory sub-system 210 may be fully operational in an on state. The memory sub-system 210 in the on state may be receiving 12V of power from a main power supply. The power from the main power supply 242 may be delivered to the memory sub-system 210 components over a main power rail. The power from the main power supply 242 may be utilized for operating active cooling measures, interfacing with the host system 220 at high speeds, processing inputs/outputs (I/Os) to/from the host 220 and managing/performing accesses of one or more of multiple memory dies of the non-volatile memory component 230 in parallel to maintain its maximum performance capabilities with respect to the host system 220.

At some point, the delivery of power from the main power supply 242 to the memory sub-system 210 may be interrupted. In response to this interruption or removal an auxiliary power supply 246 may begin to provide auxiliary power to some components of the memory subsystem 210. For example, the auxiliary power supply 246 may provide power to the data retention component 213 and/or the characteristic sensor 214. Therefore, the data retention component 213 and/or the characteristic sensor 214 may become and/or remain operational in the absence of power from the main power supply 242.

Accordingly, the characteristic sensor 214 may sense characteristics of the non-volatile memory component 230 in the absence of power from the main power supply 242. For example, the characteristic sensor 214 may sense the temperature of the non-volatile memory component 230 in the absence of power from the main power supply 242. Since the active cooling measures of the memory sub-system 210 may rely on the power from the main power supply 242 to cool the memory sub-system 210, the temperatures may reach, exceed, and/or be sustained at levels associated with an increased incidence of data degradation. However, since the power from the main power supply 242 is absent, the memory sub-system 210 may have no ability to cool itself.

The data retention component 213, utilizing axillary power from the auxiliary power supply 246 in the absence of the main power supply 242, may monitor the sensed characteristics and compare them to threshold amounts. For example, the data retention component 213 may monitor a sensed temperature, a duration of a sensed temperature, a duration of the absence of the power form the main power supply, etc. and compare them to threshold amounts that, once reaches and/or exceeded, are associated with an impending data loss event at the non-volatile memory component 230. Again, without the power from the main power supply 242, the memory sub-system 210 may be powerless to actively cool the non-volatile memory component and/or to restore power from the main power supply 242. Instead, the data retention component 213, utilizing axillary power from the auxiliary power supply 246 in the absence of the main power supply 242, may alert a user to attempt to spur an intervention.

As described above, the backend of the memory sub-system controller 215 may interface with the non-volatile memory component 230 to perform operations on the data stored in pages of the non-volatile memory component 230. In order to accommodate the high-speed processing of data stored across multiple dies in parallel at a maximum performance level, the subsystem controller 215 may require its full power allotment from the primary 12 Volt rail provided from the main power supply. As illustrated by the ellipsis in FIG. 2 , the memory sub-system 210 may include a plurality of non-volatile memory components 230. When the memory sub-system controller 215 and the non-volatile memory component 230 are receiving their full allocation of power from the main power supply 242 while in the on state, the memory sub-system controller 215 may simultaneously perform memory operations on data stored on the plurality of memory components 230, a plurality of dies of the plurality of memory components 230, and/or a plurality of pages of the plurality of memory components 230 at once when the power from the main power supply is present.

However, the data retention component 213 may, in the in the absence of power from the main power supply 242, cause the backend portion of the sub-system controller 215 to perform limited operations at once. For example, when the delivery of power from the main power supply 242 to the memory sub-system 210 is interrupted, then the auxiliary power supply 246 may begin to provide a current limited 3.3 Volts of power which may be supplied to the data retention component 213 as outlined above. Additionally, the auxiliary power supply 246 may begin to provide a current limited 3.3 Volts of power to the plurality of non-volatile memory components 230 where pages of data are stored and may provide power to the portion of the sub-system controller 215 interfacing with the plurality of non-volatile memory components 230.

The provision of power from the auxiliary power supply 246 to the plurality of nonvolatile memory components 230 and/or the portion of the memory sub-system controller 215 may be initiated responsive to the absence of power from the main power supply 246, the characteristic of the plurality of non-volatile memory components 230 reaching or exceeding a threshold value, a prediction based on the monitored characteristic that there is an impending data loss event for a page of data stored in the plurality of non-volatile memory components 230, a duration of a persistence of a data loss warning signal, reaching or exceeding a threshold amount of time, and/or the level of power remaining in an auxiliary power supply 246 reaching or crossing a threshold amount.

As described above, the auxiliary power supply 246 may be current limited and provide less current than the main power supply 242. For example, the auxiliary power supply 242 may provide 3.3 Volts of current instead of the 12 Volts provided by the main power supply 242. As such, the amount of current provided to the plurality of non-volatile memory components 230 and/or the portion of the memory sub-system controller 215 may be less than what it is provided by the main power supply 242 and less than is required by non-volatile memory components 230 and/or the portion of the memory sub-system controller 215 to accommodate the high-speed processing of data stored across multiple dies in parallel at a maximum performance level, the sub-system controller 215 when the memory sub-system is in an on state and is fully operational.

As such, the current restrictions of the auxiliary power supply 246 may restrict the amount and/or scope of operations that the non-volatile memory components 230 and/or the portion of the memory sub-system controller 215 can perform while in the absence of power from the main power supply 242. For example, the timing of reading and re-programming data into the non-volatile memory components 230 in a refresh operation may be managed in a way that avoids exceeding the current limit of the auxiliary power supply. As such, the non-volatile memory components 230 and/or the portion of the memory sub-system controller 215 may be made only partially functional when utilizing power form the auxiliary power supply 246 in the absence of power from the main power supply 242 (e.g., when the memory sub-system 210 is in an off state and/or the main power supply 242 is interrupted and/or disconnected from the memory sub-system 210).

For example, when the memory sub-system 210 is powered down and/or otherwise no longer receives power from the main power supply 242 over a main power rail, the data retention component 213 component may begin monitoring, utilizing the auxiliary power supply 246, characteristics of the plurality of non-volatile memory components 230. In some examples, the characteristic monitoring may be performed at a die-by-die of the non-volatile memory components 230 level, although other levels of characteristic monitoring are contemplated herein (e.g., an entire printed circuit board of the memory sub-system 210 including all of the memory sub-system components, particular non-volatile memory components of the plurality of nonvolatile memory components 230, etc.).

The data retention component 213 may utilize a prediction algorithm (e.g., comparing the monitored characteristic levels and/or rate of change of the same to threshold characteristic levels and/or rates of change for the same) to predict an impending data loss event. In some examples, threshold regarding the specific characteristics and specifications of the non-volatile memory component 230 may be utilized to accurately predict the limits of non-volatile memory components 230 to retain data under the observed or monitored conditions. In some examples, the amount and/or scope of the monitored characteristic data may be such that the data retention component 213 may predict which data is nearing a data loss event with die-by-die and/or page-by-page granularity.

The data retention component 213 component may cause the non-volatile memory components 230 and/or the portion of the memory sub-system controller 215 to utilize the auxiliary power supply 246 to perform a targeted refresh of the data stored in the non-volatile memory components 230. In some examples, the data retention component 213 component may cause the non-volatile memory components 230 and/or the portion of the memory sub-system controller 215 to utilize the auxiliary power supply 246 to perform a targeted refresh of specific pages of the data stored in the non-volatile memory components 230. In some examples, the data retention component 213 component may cause the non-volatile memory components 230 and/or the portion of the memory sub-system controller 215 to utilize the auxiliary power supply 246 to perform a targeted refresh of specific pages of the data stored in the non-volatile memory components 230 that were identified as predicted to be nearing and/or most as risk for the impending data loss event. In some examples, the data retention component 213 component may cause the non-volatile memory components 230 and/or the portion of the memory sub-system controller 215 to utilize the auxiliary power supply 246 to perform a targeted refresh of specific dies where the data is stored in the non-volatile memory components 230 that were identified as predicted to be nearing and/or most at risk for the impending data loss event. Additionally, the data retention component 213 component may cause the non-volatile memory components 230 and/or the portion of the memory sub-system controller 215 to utilize the auxiliary power supply 246 to perform a targeted refresh of specific pages where the data is stored in the non-volatile memory components 230 based on a priority assigned to the data in those specific pages (e.g., pages where higher priority data is stored may be refreshed before those pages where lower priority data is stored). Additionally, the data retention component 213 component may cause the non-volatile memory components 230 and/or the portion of the memory sub-system controller 215 to utilize the auxiliary power supply 246 to perform a targeted refresh of specific dies where the data is stored in the non-volatile memory components 230 based on a priority assigned to the data in those specific dies (e.g., dies where higher priority data is stored may be refreshed before those die where lower priority data is stored).

As described above, in order to not exceed the limited current capacity of the auxiliary power supply 246, only a portion of the memory-subsystem controller 215 may be supplied with power and/or utilized in the targeted refresh operations. Other portions of the memory-subsystem controller 215 may be disabled and/or not supplied with power when the utilizing power from the auxiliary power supply 246. Further, the non-volatile memory components 230 and/or the portion of the memory sub-system controller 215 may only be partially operational. For example, the non-volatile memory components 230 and/or the portion of the memory sub-system controller 215 may have their operational capabilities limited (e.g., other operational capabilities restricted, disabled, and/or cut off from power consumption, etc.).

For example, a limited amount of current (e.g., 3.3 Volts) may be supplied to the nonvolatile memory components 230 and/or the portion of the memory sub-system controller 215 from the auxiliary power supply 246 in the absence of power from the main power supply 242. The limited amount of current may be utilized to provide the portion of the memory sub-system controller 215 with access to a limited number of the non-volatile memory components 230 and/or a limited number of dies of the non-volatile memory components 230 at a time for refresh operations.

A limited number of the non-volatile memory components 230 and/or a limited number of dies of the non-volatile memory components 230 may be an amount of non-volatile memory components 230 and/or their dies than is accessible by the memory sub-system controller 215 during full operation in an on state with a full power allocation of the main power supply 242 provided across the main power rail. For example, the memory sub-system controller 215 may only have access to one non-volatile memory components 230 and/or die at a time to perform refresh operations when utilizing the auxiliary power supply 246. In some examples, the memory sub-system controller 215 and/or non-volatile memory components 230 may utilize 2.5 Volts and 1.2 Volts for performing such limited operations, which may be regulated down by regulator 248 from the 3.3 Volts provided by an auxiliary power supply 246 and routed to the non-volatile memory components 230 and/or the portion of the memory sub-system controller 215 being utilized for the targeted refresh operations.

As described above, the targeted refresh operations may involve reading the data out of the particular die or page being refreshed and re-programming it back in responsive to a prediction of an impending data loss event by the data retention component 213. It should be appreciated that the goal of the targeted refresh operations is to complete the refresh operation before the data loss even occurs and the data is unrecoverable. As such, the targeted refresh operations may be scheduled to be executed and/or be executed prior to the data loss event such that the refresh is completed prior to the predicted occurrence of the data loss event. As such, an amount of data in the non-volatile memory components 230 to be refreshed may be utilized as part of the consideration of when to schedule the execution of the targeted refresh. For example, the more data that needs to be refreshed the longer the period of time that may be allocated for completing the targeted refresh prior to the data loss event.

In addition, the auxiliary power supply 246 may be a limited reservoir of power (e.g., a battery, a capacitor, etc.). As such, the amount of targeted data refreshing that may be performed may be limited by the amount of power that the auxiliary power supply 246 can provide before it is exhausted. Therefore, in some examples, the portion of the memory sub-system controller 215 and/or non-volatile memory components 230 may perform the targeted refresh until the power from the auxiliary power supply 246 is exhausted. In some examples, where the amount of data needing to be refreshed to avoid all predicted impending data loss events would require more power than is available from the auxiliary power supply 246, the portion of the memory subsystem controller 215 and/or non-volatile memory components 230 may perform the targeted refresh starting with the data predicted to be most at risk of loss and/or data with a highest priority designation first and proceeding along to the next most at risk of loss and/or next highest priority until the auxiliary power supply 246 is exhausted.

In some examples, the data retention component 213 may generate a signal to indicate that the targeted refresh is being performed. In some examples, the targeted refresh signal may be separate from the data loss warning signal. For example, During the sequence of refreshing the data, the unit may make audible and visual indications of the process that is taking place. This could be accomplished using a piezo buzzer and by toggling the disk activity signal on the drive. Alternatively, onboard LEDs present on the memory sub-system 210 could be toggled as to indicate that the data refresh operation is taking place.

In addition, the memory sub-system 210 may include an electrically erasable programmable read-only memory (EEPROM). The EEPROM may be utilized to store inventory management information for the data stored in the non-volatile memory components 230. For example, the EEPROM may include a record of where (e.g., which non-volatile memory component 230 of a plurality of non-volatile memory components data is stored at, which die of a non-volatile memory component 230 data is stored at, which page of a non-volatile memory component 230 data is stored at, etc.) data is stored in the non-volatile memory components 230. The EEPROM may include a record of a temperature of a non-volatile memory component 230 of a plurality of non-volatile memory components where data is stored at, temperature of a die of a non-volatile memory component 230 where data is stored at, temperature of a page of a nonvolatile memory component 230 where data is stored at, etc. The EEPROM may include a record of an elapsed time since a non-volatile memory component 230 of a plurality of non-volatile memory components where data is stored at, a die of a non-volatile memory component 230 where data is stored at, a page of a non-volatile memory component 230 where data is stored at, etc. stopped receiving power from a main power supply 242. The EEPROM may include a record of a priority assigned to data stored at a non-volatile memory component 230 of a plurality of nonvolatile memory components, a die of a non-volatile memory component 230, a page of a nonvolatile memory component 230, etc. In the absence of the main power supply 242, the EEPROM may receive power from the auxiliary power supply 246. The EEPROM, powered utilizing the auxiliary power supply 246 in the absence of the main power supply 242, may be readable by a host 220 and/or by a data retention component 213 for inventory management and/or targeting of data to be refreshed.

FIG. 3 is flow diagram corresponding to a method 360 for memory sub-system data retention via refresh in accordance with some embodiments of the present disclosure. The method 360 can be performed by processing logic that can include hardware (e.g., processing device, circuitry, dedicated logic, programmable logic, microcode, hardware of a device, integrated circuit, etc.), software (e.g., instructions run or executed on a processing device), or a combination thereof. In some embodiments, the method 360 is performed by the data retention component 113 of FIG. 1 . Although shown in a particular sequence or order, unless otherwise specified, the order of the processes can be modified. Thus, the illustrated embodiments should be understood only as examples, and the illustrated processes can be performed in a different order, and some processes can be performed in parallel. Additionally, one or more processes can be omitted in various embodiments. Thus, not all processes are required in every embodiment. Other process flows are possible.

At operation 362, delivery of power from a main power supply to a memory subsystem may be interrupted. The main power supply may be a 12 Volt power supply which supplies a full allotment of power to each of the components of the memory sub-system over a main power rail while the memory subsystem is in a fully operational and/or on sate. When delivery of power from the main power supply to the memory sub-system is interrupted, an auxiliary power supply 246 may begin to provide power from the auxiliary power source to some of the components of the memory sub-system.

For example, power from the auxiliary power supply may be provided (e.g., when delivery of power from a main power supply to a memory sub-system comprising a plurality of non-volatile memory components is interrupted) to a portion of a memory sub-system controller and/or a non-volatile memory component interfacing therewith. For example, power from the auxiliary power supply may be provided to a data retention component and/or a characteristic sensor. As such, when delivery of power from the main power supply to the memory sub-system is interrupted, the power from the auxiliary power supply may be supplied to a processing device of the memory sub-system to: monitor a characteristic of the memory sub-system associated with data retention at a plurality of non-volatile memory components while power delivery from the main power supply to the memory sub-system is interrupted.

For example, the processing device of the memory sub-system may be utilized to monitor a temperature of a particular portion of the plurality of non-volatile memory components (e.g., a particular non-volatile memory component of a plurality of non-volatile memory components, a particular die in the plurality of non-volatile memory components, a particular page in the plurality of non-volatile memory components, etc.). The processing device of the memory sub-system may be utilized to monitor an elapsed amount of time of an interruption of power delivery from the main power supply to the memory sub-system.

Additionally, power from the auxiliary power supply may be supplied to a processing device of the memory sub-system to generate, based on the monitored characteristic, a prediction that a particular portion of the plurality of non-volatile memory components will experience the impending data loss event. For example, power from the auxiliary power supply may be supplied to a processing device of the memory sub-system to generate a prediction that a particular non-volatile memory component of a plurality of non-volatile memory components, a particular die in the plurality of non-volatile memory components, a particular page in the plurality of nonvolatile memory components, etc. will experience an impending data loss event.

The prediction that a particular portion of the plurality of non-volatile memory components will experience the impending data loss event may be based on comparing the monitored characteristic to a threshold value of the monitored characteristic associated with the data loss event. For example, once a monitored characteristic crosses a threshold amount and/or is projected to cross a threshold amount within a specific period of time, the prediction of an impending data loss event may be generated.

At operation 364, when power delivery from the main power supply to a memory subsystem comprising a plurality of non-volatile memory components is interrupted, power from an auxiliary power supply may be provided to a portion of a controller interfacing with the nonvolatile memory components to perform a targeted refresh operation on data stored in a particular portion. For example, power from an auxiliary power supply may be provided to a portion of a controller interfacing with the non-volatile memory components to perform a targeted refresh operation on data stored in a particular portion responsive to the predication, generated while power delivery from the main power supply to the memory sub-system is interrupted, that the particular portion of the plurality of non-volatile memory components will experience an impending data loss event.

Additionally, power from an auxiliary power supply may be provided to a portion of a controller interfacing with the non-volatile memory components to perform additional targeted refresh operations on data stored in other portions of the plurality of non-volatile memory components predicted to experience an impending data loss event. The additional targeted refresh operations may be performed utilizing the power from the auxiliary power source until delivery of power from the main power supply to the memory sub-system is restored and/or until the auxiliary power source is exhausted.

FIG. 4 is a block diagram of an example computer system 470 in which embodiments of the present disclosure may operate. For example, FIG. 4 illustrates an example machine of a computer system 470 within which a set of instructions, for causing the machine to perform any one or more of the methodologies discussed herein, can be executed. In some embodiments, the computer system 470 can correspond to a host system (e.g., the host system 120 of FIG. 1 ) that includes, is coupled to, or utilizes a memory sub-system (e.g., the memory sub-system 110 of FIG. 1 ) or can be used to perform the operations of a controller (e.g., to execute instructions to perform operations corresponding to the data retention component 113 of FIG. 1 ). In alternative embodiments, the machine can be connected (e.g., networked) to other machines in a LAN, an intranet, an extranet, and/or the Internet. The machine can operate in the capacity of a server or a client machine in client-server network environment, as a peer machine in a peer-to-peer (or distributed) network environment, or as a server or a client machine in a cloud computing infrastructure or environment.

The machine can be a personal computer (PC), a tablet PC, a set-top box (STB), a Personal Digital Assistant (PDA), a cellular telephone, a web appliance, a server, a network router, a switch or bridge, or any machine capable of executing a set of instructions (sequential or otherwise) that specify actions to be taken by that machine. Further, while a single machine is illustrated, the term “machine” shall also be taken to include any collection of machines that individually or j ointly execute a set (or multiple sets) of instructions to perform any one or more of the methodologies discussed herein.

The example computer system 470 includes a processing device 472, a main memory 574 (e.g., read-only memory (ROM), flash memory, dynamic random access memory (DRAM) such as synchronous DRAM (SDRAM) or Rambus DRAM (RDRAM), etc.), a static memory 476 (e.g., flash memory, static random access memory (SRAM), etc.), and a data storage system 482, which communicate with each other via a bus 488.

The processing device 472 represents one or more general-purpose processing devices such as a microprocessor, a central processing unit, or the like. More particularly, the processing device can be a complex instruction set computing (CISC) microprocessor, reduced instruction set computing (RISC) microprocessor, very long instruction word (VLIW) microprocessor, or a processor implementing other instruction sets, or processors implementing a combination of instruction sets. The processing device 472 can also be one or more special-purpose processing devices such as an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), a digital signal processor (DSP), network processor, or the like. The processing device 472 is configured to execute instructions 480 for performing the operations and steps discussed herein. The computer system 470 can further include a network interface device 478 to communicate over the network 486.

The data storage system 482 can include a machine-readable storage medium 484 (also known as a computer-readable medium) on which is stored one or more sets of instructions 480 or software embodying any one or more of the methodologies or functions described herein. The instructions 480 can also reside, completely or at least partially, within the main memory 474 and/or within the processing device 472 during execution thereof by the computer system 470, the main memory 474 and the processing device 472 also constituting machine-readable storage media. The machine-readable storage medium 484, data storage system 482, and/or main memory 474 can correspond to the memory sub-system 110 of FIG. 1 .

In one embodiment, the instructions 480 include instructions to implement functionality corresponding to a data retention component (e.g., the data retention component 113 of FIG. 1 ). While the machine-readable storage medium 484 is shown in an example embodiment to be a single medium, the term “machine-readable storage medium” should be taken to include a single medium or multiple media that store the one or more sets of instructions. The term “machine-readable storage medium” shall also be taken to include any medium that is capable of storing or encoding a set of instructions for execution by the machine and that cause the machine to perform any one or more of the methodologies of the present disclosure. The term “machine-readable storage medium” shall accordingly be taken to include, but not be limited to, solid-state memories, optical media, and magnetic media.

Some portions of the preceding detailed descriptions have been presented in terms of algorithms and symbolic representations of operations on data bits within a computer memory. These algorithmic descriptions and representations are the ways used by those skilled in the data processing arts to most effectively convey the substance of their work to others skilled in the art. An algorithm is here, and generally, conceived to be a self-consistent sequence of operations leading to a desired result. The operations are those requiring physical manipulations of physical quantities. Usually, though not necessarily, these quantities take the form of electrical or magnetic signals capable of being stored, combined, compared, and otherwise manipulated. It has proven convenient at times, principally for reasons of common usage, to refer to these signals as bits, values, elements, symbols, characters, terms, numbers, or the like.

It should be borne in mind, however, that all of these and similar terms are to be associated with the appropriate physical quantities and are merely convenient labels applied to these quantities. The present disclosure can refer to the action and processes of a computer system, or similar electronic computing device, that manipulates and transforms data represented as physical (electronic) quantities within the computer system’s registers and memories into other data similarly represented as physical quantities within the computer system memories or registers or other such information storage systems.

The present disclosure also relates to an apparatus for performing the operations herein. This apparatus can be specially constructed for the intended purposes, or it can include a general purpose computer selectively activated or reconfigured by a computer program stored in the computer. Such a computer program can be stored in a computer readable storage medium, such as, but not limited to, any type of disk including floppy disks, optical disks, CD-ROMs, and magnetic-optical disks, read-only memories (ROMs), random access memories (RAMs), EPROMs, EEPROMs, magnetic or optical cards, or any type of media suitable for storing electronic instructions, each coupled to a computer system bus.

The algorithms and displays presented herein are not inherently related to any particular computer or other apparatus. Various general purpose systems can be used with programs in accordance with the teachings herein, or it can prove convenient to construct a more specialized apparatus to perform the method. The structure for a variety of these systems will appear as set forth in the description below. In addition, the present disclosure is not described with reference to any particular programming language. It will be appreciated that a variety of programming languages can be used to implement the teachings of the disclosure as described herein.

The present disclosure can be provided as a computer program product, or software, that can include a machine-readable medium having stored thereon instructions, which can be used to program a computer system (or other electronic devices) to perform a process according to the present disclosure. A machine-readable medium includes any mechanism for storing information in a form readable by a machine (e.g., a computer). In some embodiments, a machine-readable (e.g., computer-readable) medium includes a machine (e.g., a computer) readable storage medium such as a read only memory (“ROM”), random access memory (“RAM”), magnetic disk storage media, optical storage media, flash memory devices, etc.

In the foregoing specification, embodiments of the disclosure have been described with reference to specific example embodiments thereof. It will be evident that various modifications can be made thereto without departing from the broader spirit and scope of embodiments of the disclosure as set forth in the following claims. The specification and drawings are, accordingly, to be regarded in an illustrative sense rather than a restrictive sense. 

What is claimed is:
 1. A method, comprising: providing, when delivery of power to a memory sub-system comprising a plurality of non-volatile memory components from a main power supply is interrupted, power from an auxiliary power supply to a portion of a controller interfacing with the non-volatile memory components to: responsive to a prediction, generated when the delivery of the power from the main power supply to the memory sub-system is interrupted, that a particular portion of the plurality of non-volatile memory components will experience an impending data loss event, perform a targeted refresh operation of data stored in the particular portion.
 2. The method of claim 1, further comprising utilizing, when the delivery of the power to the memory sub-system from the main power supply is interrupted, the power from the auxiliary power supply to supply power to a processing device of the memory sub-system to: monitor a characteristic of the memory sub-system associated with data retention at the plurality of non-volatile memory components when the delivery of the power to the memory sub-system from the main power supply is interrupted.
 3. The method of claim 2, wherein utilizing, when the delivery of the power to the memory sub-system from the main power supply is interrupted, the power from the auxiliary power supply to power the processing device of the memory sub-system to monitor the characteristic of the memory sub-system associated with data retention at the plurality of non-volatile memory components when the delivery of the power to the memory sub-system from the main power supply is interrupted includes utilizing, when the delivery of the power to the memory sub-system from the main power supply is interrupted, the processing device of the memory sub-system to monitor a temperature of the particular portion of the plurality of non-volatile memory components.
 4. The method of claim 2, wherein utilizing, when the delivery of the power to the memory sub-system from the main power supply is interrupted, the power from the auxiliary power supply to provide the power to the processing device of the memory sub-system to monitor the characteristic of the memory sub-system associated with data retention at the plurality of non-volatile memory components when the delivery of the power to the memory sub-system from the main power supply is interrupted includes utilizing, when the delivery of the power to the memory sub-system from the main power supply is interrupted, the processing device of the memory sub-system to monitor a duration of the interruption of the delivery of the power to the memory sub-system from the main power supply.
 5. The method of claim 2, further comprising utilizing, when the delivery of the power to the memory sub-system from the main power supply is interrupted, the power from the auxiliary power supply to provide power to the processing device of the memory sub-system to: generate, based on the monitored characteristic, the prediction that the particular portion of the plurality of non-volatile memory components will experience the impending data loss event.
 6. The method of claim 5, further comprising utilizing, when the delivery of the power to the memory sub-system from the main power supply is interrupted, the power from the auxiliary power supply to provide the power to the processing device of the memory sub-system to generate, based on the monitored characteristic, the prediction that the particular portion of the plurality of non-volatile memory components will experience the impending data loss event by comparing the monitored characteristic to a threshold value of the monitored characteristic associated with the data loss event.
 7. The method of claim 5, further comprising performing additional targeted refresh operations of data stored in other portions of the plurality of non-volatile memory components predicted to experience an impending data loss event until the interruption of the delivery of the power to the memory sub-system from the main power supply is ended.
 8. An apparatus, comprising: a plurality of non-volatile memory components storing pages of data; a data retention component configured to operate, utilizing power from an auxiliary power supply in an absence of power from a main power supply, to: monitor a characteristic of the plurality of non-volatile memory components; and predict, based on the monitored characteristic, an impending data loss event for a page of data stored in the plurality of non-volatile memory components; and a portion of a controller configured to operate utilizing the power from the auxiliary power supply in the absence of the power from the main power supply, to: perform a targeted refresh operation of data stored on the page responsive to the prediction by the data retention component.
 9. The apparatus of claim 8, wherein the data retention component is part of the controller.
 10. The apparatus of claim 8, wherein the controller comprises a first processing device and wherein the data retention component comprises a second processing device.
 11. The apparatus of claim 8, wherein the portion of the controller is a portion that interfaces with the plurality of memory components to perform memory operations on only a limited number of the plurality of memory components at once utilizing the power from the auxiliary power supply in the absence of the power from the main power supply.
 12. The apparatus of claim 11, wherein the portion of the controller simultaneously manages the plurality of memory components to perform memory operations on data stored on the plurality of memory components at once when the power from the main power supply is present.
 13. The apparatus of claim 11, wherein the controller includes a second portion that interfaces with a host to processes inputs and outputs from the host when the power from the main power supply is present, and wherein the second portion is disabled when utilizing the power from the auxiliary power supply in the absence of the power from the main power supply.
 14. The apparatus of claim 8, further comprising a temperature sensor to monitor, utilizing the power from the auxiliary power supply in the absence of the power from the main power supply, the temperature of the plurality of memory components as the monitored characteristic.
 15. The apparatus of claim 8, further comprising an electrically erasable programmable read-only memory (EEPROM), powered utilizing the power from the auxiliary power supply in the absence of the power from the main power supply, to be readable by a host for inventory management in the absence of the power from the main power supply.
 16. A system, comprising: a plurality of non-volatile memory components; a processing device configured to operate, utilizing power from an auxiliary power supply in an absence of power from a main power supply, to: identify a portion of the plurality of non-volatile memory components at risk of data retention failures; and cause a controller, operating in a reduced capacity utilizing an auxiliary power supply in the absence of the power from the main power supply, to address the portion of the plurality of non-volatile memory components identified as at risk of data retention failures on a per memory component basis to refresh data at risk of loss.
 17. The system of claim 16, further comprising the processing device configured to operate, utilizing the power from the auxiliary power supply in the absence of the power from the main power supply, to identify the portion of the plurality of non-volatile memory components at the risk of the data retention failures based on a comparison of a monitored temperature of the plurality of non-volatile memory components and a monitored amount of time since the power from the main power supply was interrupted to a threshold level indicative of an impending data loss event.
 18. The system of claim 16, wherein the controller utilizes the power from the auxiliary power supply to refresh the data at risk of loss by reading the data values out of the portion of the plurality of non-volatile memory components and writing it back to the plurality of non-volatile memory components.
 19. The system of claim 16, further comprising the processing device configured to operate, utilizing the power from the auxiliary power supply in the absence of the power from the main power supply, to generate a warning responsive to the identification of the portion of the plurality of non-volatile memory components at the risk of the data retention failures.
 20. The system of claim 16, wherein the plurality of non-volatile memory components comprises a NAND flash memory array. 